Exhaust gases of an automobile engine are released to the atmosphere through an exhaust pipe, and this exhaust pipe is subjected to repeated stress owing to such as the roll behavior and vibration of the engine, with the result that there is a possibility of causing a fatigue failure of the exhaust pipe, and there are also cases where the engine vibration causes the exhaust pipe to resonate, thereby deteriorating the quietness of the compartment interior. To overcome such problems, a means has been adopted to absorb the stress by disposing an exhaust pipe joint at a predetermined portion of the exhaust pipe.
As a spherical annular seal member which is used in the exhaust pipe joint, for example, one is proposed in Patent Document 1 which includes a spherical annular base member defined by a cylindrical inner surface, a partially convex spherical surface, and large- and small-diameter side annular end faces of the partially convex spherical surface; and an outer layer formed integrally on the partially convex spherical surface of this spherical annular base member.